Method of manufacture of artificial silk



Aug. 3l 1926. 1,597,684

. c. c. JEssEN METHOD OF MANUFACTURE 0F ARTIFICIAL SILK I Filed Nov. 10,1924 gnou/diez Patented Aug. 31, 1926.

UNITED STATES 1,597,684 PATENT OFFICE.

CIEIARLES C. J ESSEN, OF WILMINGTON, DELAWARE, ASSIGNOR TO ATLAS POWDERCOM- PANY, OF WILMINGTON, DELAWARE, A CORPORATION 0F DELAWARE.

METHOD OF. MANUFACTURE OF ARTIFICIAL SILK.

Application led. November 10, 1924. Serial No. 749,094.

This invention relates to a method of manufacture of artificial silk andmore particularly to a manner of handling the sampJ to preventmechanical damage to the silk from handling in the several steps throughwhich it passes.

In the manufacture of artificial silk cellulose is reduced to a syrupvlike consistency by various methods. Among these are the nitro-method,the viscose method, and the copper-ammonia method. In these severalmethods it becomes necessary to remove residual substances from thethreads after the solution has been discharged from the spinnerets andbrought to thread-like form by its passage through a suitablesolidifying or precipitating bath. Y

For purposes of clearness I will describe the invention as applied tothe copper-ammonia method of manufacturing artificial silk, though, aswill be hereinafter set forth, the invention is of utility in connectionwith the other methods named.

i In the manufacture -of artificial silk by the copper ammonia process,cellulose is reduced to a syrup like solution by the action of coppersulphate and ammonia. This solution is forced through the fine holes ofspinnerets directly into an alkaline precipitating bath which. instantlysolidifies it to such an extent that it becomes a series of well definedthreads of such strength as to permit of their being handled in thesubsequent operations. It is very necessary however, to remove from thethreads, substantially all traces of the chemicals used in bringing thecellulose into solution form. Some of the ammonia is removed in thealkaline precipitating bath and most of the remainder of the ammonia isremoved by evaporation in the subsequent operations.

The removal of the copper is not eect ed as easily as the removal of thehighly `volatile ammonia and, heretofore, the mechanical handling towhich the silk was subjected in the removal of the copper has resultedin considerable damage to the same with consequent waste and loss.

In the manufacture of artificial silk, there are at present in 4generaluse, two methods of spinning. One is the so-called spool or bobbinspinning, and the other, pot spinning. In the first, or bobbin method,the individual and untwisted threads emerging from the precipitatingbath are collected on rotating cylinders, spools or bobbins. The

-ess causes a waste of material and labor because if one filamentbreaks, it is `not picked up by the others, and causes tangling.

In the second, or pot method, the-threads in parallel are passed into arapidly rotating centrifuge basket, or pot. A suitable guide vortraverse lays the thread against the wall of the pot, in the form of acylindrical cake. The thread entering the pot is twisted by the rotationof the pot. When the desired quantity of thread has been collected, thepot is removed from the spinning machine, the thread reeled up in theform of a skein and given the necessary chemical and mechanicaltreatments to obtain the finished product. This method is superior tothe rst method given above, but the thread is still liable to receivemechanical damage through handling the relatively weak thread in skeinform during the intermediate treatments.

Broadly stated, my invention consists of plurality of spun threads, uponany suitable support, where it may be maintained under such slighttension, as will prevent it from tangling, and to subject the silk toall `subsequent operations, such as those necessary to remove thecopper; washing and drying,

while it is still mounted upon said support. 'y

rectly from the pot of the centrifuge, and 100 winding it upon acylinder, spool orA bobbin and subjecting it to a chemical treatment todecopp the same, i. e. to remove the residual copper, during suchwinding operation. This gives the strand a uniform 105 chemicaltreatment and eliminates many of the defects which are found in threadswhich do not receive a uniform chemical treatment.

The cylinders, spools, bobbins and the 11 e5 winding the twisted strand,composed of a the support. In other words, the silk is brought from thepoint of spinning to thel point of final drying on the same support(upon which it is initially wound,so that it bloes no?r have to betouched by human hands and is maintained in such form that it'can notbecome tangled, throughout its progress.

I do not limit myself as to the exact form of the spool or cylinder onwhich the thread is wound. The spool may be slightly tapered, i. e. of aconical shape and may or may not have flanges on one or both ends. Nordo I limit myself to the method of giving the thread the treatment or tothe type of treatment. The cylinder may rotate about a horizontal axis,and may be partially submerged in the liquid -bath used for thetreatment, or the liquid may be applied by spraying it on`the spool, orby flowing it on by a suitable device.

One form in which the decopping apparatus may be embodied is illustratedin the single figure of the accompanying drawing. This figure is a viewpartly in side elevation and partly in section of a simple form ofapparatus for simultaneously windin the strand upon a cylinder andsubjecting it to a bath for removing the copper, during such windingaction. In the drawing, 5 designates the pot of a centrifuge in which aplurality of parallel threads have been twisted into strand formation asindicated at 6. rllhe strand 7 is led from the cake, deposited in thepot; through a support 8 and to and through a pig tail guide 9 carriedby the lower end of a traverse arm 10. This traverse arm is Eivoted at11 and is moved in one direction y a link 12 and a swinging arm 13 andin r the other direction by a spring 14. The

arm 13 is moved against the tension of the spring by the action of a pin15 upon a rotative worm wheel 16. The worm Wheel 16 is mounted upon adrive shaft 17 and imparts motion to a worm 18 and shaft 19. J The shaft19 carries a mandrel 20 upon which a cylinder 21 may be slipped, saidcylinder being of such size as to frictionally engage the mandrel 2O androtate therewith. The action of the traverse arm in conjunction With therotation of the Inandrel and cylinder, causes theA strand to bedeposited upon the cylinder in an open and porous mass. A bath of liquidindicated at 22 is so disposed with respect to the mandrel and c linderthat the lower portion of the v,cylinder and the strands wound thereonrotate in the bath. Each successive layer of strands is directly exposedto the action of the liquid 22 and the strands.

are wound up in open and porous formation to permit the liquid to findready passage 'to all parts of the mass throughout the winding ofstrands upon said cylinder;

It is to be understood that I do not claim as my invention theparticular liquid employed for the removal of the copper. Dilutesulphuric acid is commonly employed for this purpose. It is commonpractice to remove the copper from the silk by the action of thischemical. The invention resides more particularly in the manner and timeof applying the liquid to the artificial silk for the removal ofresidual chemicals left from the preparation of the solution from whichthe threads are formed. The chemical that' it is particularly desiredtoremove in the copper ammonia process is the residual copper, but it ismanifest that the method is of utility in connection with either theviscose or the nitro processes. In the viscose process, it becomesnecessary to remove residual sulphur compounds while in the nitroprocess it is necessary to dentrate the nitrocellulose filaments.

The cylinders 21 may be formed of any suitable material. I have foundbakelite suitable for this purpose. After the strands are wound upon thecylinders, said cylinders constitute supports or carriers upon which thestrands remain under light tension during the subsequent operations ofwashing and drying. These cylinders may be conducted to suitable washingapparatus Where they are sprayed with clear water and then be placed indrying ovens of conventional form and dried. After being dried the silkmay be drawn directly from the cylinders to the swifts of a skeiningmachine.

From the foregoing description it will be seen that under this inventionthe strands are taken directly from the spinning machine and placed uponsupports under light tension and are maintained in that con dition andupon said supports throughout the operations of decopping, washing,drying and skeining to brlng` them into their completed commercial form.The result of this is that it has been found in actual ractice thatpractically all of the flaws an imperfections heretofore met with in theproduction of artificial silk are eliminated and a high grade silk ishad lat a minimum cost, because the usual waste and loss resulting fromtangled skeins and the like, is avoided.

Having described my invention what I claim is:

1. The 'herein described method of manufacturing artificial silk whichconsists of winding the strands of spun and twisted threads, directlylfrom the centrifu e pot, after the latter has been removed om aspinning machine, upon a freely removable cylinder, while rotating thelatter in the` presence of a bath. adapted to chemically treat' thestrands, and thereafter Ec'arryin said cylinder bodily and with thestran s under light tension thereon, through washing and drying steps.

2. The herein described method of manufacturing artiicial silk whichconsists of Winding the strands of spun and twisted threads, directlyfrom the centriu e pot, after the latter has been removed om a spinningmachine, upon a freely removable,

Water and heat proof cylinder, while r0- tating the latter 1n thepresence of a bath adapted to chemically treat the strands, andthereafter carrying said cylinder bodily and with the strands underlight tension thereon, through washing and drying steps, the

latter steps being at elevated temperature.

In testimony whereof he aiixes his signa-` ture.

CHARLES o. JEssEN.

